A pocket veto is a legislative tactic that allows the president to indirectly veto a bill.
The U.S. Constitution requires the President to sign a bill within the 10 days if Congress is in session. If Congress is in session and the president fails to sign the bill, it becomes law without his signature. However, if Congress adjourns before the ten days are up and the President does not sign the bill, it will not become law. Ignoring it — or putting it in your pocket — has been called a pocket veto.